Lake has been with the team as a DB coach since 2011.
In that time the Steelers defense has ranked: 1, 6, 14, 18, 11, and 10 in points allowed. Every year but one in the top half of the league.
In that time the Steelers have drafted 12 defensive backs (
http://www.pro-football-reference.co.../pit/draft.htm). 7 are no longer with the team and I'm not sure if a few of them are even in the league. Golson, Davis, Burns, Sutton, and Allen all appear to have a bright NFL future if we are optimistic.
The other flops on that draft list - is that on Lake or the scouts? We don't know. But man, they sure swung and missed on a TON of DBs in the past half dozen or so years.